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The circuit will give us 10 amps (12 amps surge) with performance that equals or exceeds any commercial unit. The circuit even has a current limiting feature which is a more reliable system than most commercial units have.... [read more]

Many people experienced sleeping well in natural surroundings, into a tent or a wooden hut. This fact is due not only to the healthy atmosphere but also from our unconscious ability to perceive natural Earth's magnetic-fields. The circuit generates this type of Geo-magnetic-fields and lets us perceive them: in this manner our brain is surrounded by an ideal environment for a sound sleep.... [read more]

In operation, when the relay is deactivated, the 100uF capacitor will charge to 6 volts. When the button is pressed, the capacitor will apply 6 volts to the MOSFET gate turning it on. The capacitor voltage (and gate voltage) will fall from 6 to 3 volts in about 200 mS which should be enough time for the relay contacts to move. For very slow relays, a larger capacitor may be needed.... [read more]

This 555 timer circuit toggles a relay when a button is pressed. Pins 2 and 6, the threshold and trigger inputs, are held at 1/2 the supply voltage by the two 10K resistors. When the output is high, the capacitor charges through the 100K resistor, and discharges when the output is low. When the button is pressed, the capacitor voltage is applied to pins 2 and 6 which causes the output to change to the opposite state.... [read more]

This current-limiting circuit, shown in this example as part of a small bench power supply, could in principle be used in conjunction with any dual-rail current source. The part of the circuit to the left of the diagram limits the current at the input to the dual voltage regulator (IC4 to IC7) so that it is safely protected against overload. The circuit shown produces outputs at ±15 V and ±5V. The voltage regulators at the outputs (7815/7805 and 7915/7905) need no further comment; but the current-limiting circuit itself, built around an LM317 and an LM337, is not quite so self-explanatory.... [read more]

It sounds rather mysterious: a switch that is controlled by its ambient temperature. All without the touch of a human hand, except for when you’re building this sort of electronic thermostat. There are a lot of handy uses for a thermally controlled switch. If the temperature inside your PC gets too high sometimes, the circuit can switch on an extra fan. You can also use to switch on an electric heater automatically if the room temperature is too low. There are innumerable potential applications for the thermostat described here.... [read more]